Insulin protamine zinc recombinant human insulin

Quinpirole dihydrochloride (Sigma-Aldrich, St. Louis, MO, USA) and (±) DOM hydrochloride (NIDA Research Technology Branch, Rockville, MD, USA) were dissolved in sterile 0.9% saline and administered i.p. Insulin (protamine zinc recombinant human insulin; Boehringer Ingelheim Vetmedica, Inc., St. Joseph, MO) was dissolved in sterile 0.9% saline and injected i.p. All injection volumes were 1 ml/kg body weight.

Quinpirole dihydrochloride (Sigma-Aldrich, St. Louis, MO, USA) and cocaine hydrochloride (NIDA Research Technology Branch, Rockville, MD, USA) were dissolved in sterile 0.9% saline and administered i.p. in a volume of 1 ml/kg body weight. Insulin (protamine zinc recombinant human insulin; Boehringer Ingelheim Vetmedica, Inc., St. Joseph, MO) was dissolved in sterile 0.9% saline and injected i.p. in a volume of 1 mg/kg body weight. L-741,626 (Tocris, Ellisville, MO, USA) was dissolved in 5% ethanol with 1 M HCl and injected s.c., typically in a volume of 1 ml/kg body weight. Due to its limited solubility, L-741,626 was prepared at a concentration of 1.78 mg/mL for the largest dose examined (3.2 mg/kg), resulting in injection volumes larger than 1 ml/kg body weight.